Within the context of oil well drilling operations, there presently exists many devices and methods for determining the composition of the geological formation being drilled. The following delineated examples of these devices and systems are representative of the relevant prior art:
1. Running gamma ray and/or beta ray transmitters, or the like downhole, by means of wireline apparatus, and utilizing this transmitter to transmit gamma and/or beta rays through the formation, wherein these rays are reflected by the formation back to the transmitter, which further comprises detector means for receiving these reflected gamma and/or beta rays, and measuring and recording these signals by means of a measurer/recorder device situated on the rig floor, which data is interpreted by a skilled log analyst situated thereat. It is important to note that to conduct this measurement of the resistance of the formation to the rays requires that all drilling be stopped, thus resulting in rig downtime, which is very expensive and inefficient. It should also be noted that the density of the formation is inversely proportional to the degree of penetration of the gamma or beta rays within the formation, as the densest formation provides the greatest resistance to the gamma or beta rays being penetrated through the formation. The measurer/recorder device continuously records the degree of penetration of the gamma or beta rays in graphical form, so that the resistance of the rock formation, and therefore the compositon of the rock formation, can be determined by the skilled log analyst who interprets the data at the rig floor;
2. A spontaneous potential curve generator device which transmits an electrical signal from the surface of the formation through the various strata of the formation, to any desired depth and back to the surface of the earth, wherein the device measures the potential across the formation, and generates a spontaneous potential curve which is a graphical representation of the potential which exists across each preselected interval of the formation, for example, every ten feet thereof. The degree of the potential applied thereacross varies with the different types of geological rock formations, or strata, thus enabling a skilled person to interpret this graphical data and determine the type and quality of the formation being drilled downthrough. It is important to note that the operation of the spontaneous potential curve generator also requires that all drilling be stopped, thereby resulting in rig downtime, thereby resulting in great expense and inefficiency in the oil rig operations;
3. The third method of determining the composition of the rock formation being drilled through is by having a skilled mud logging engineer take actual samples of the cuttings or shavings which are present in the drilling mud being circulated through the well bore, as they are recirculated through the well bore to the surface of the well, and by having said mud logging engineer estimate the amount of sand and/or other substances that are in the effluent, and by plotting a graph of the amount of said sand or other substances contained by the drilling mud providing and indication of what type of rock formation is being drilled through, for example, sandstone, shale, etc., and further, providing an indication of the amount of oil and/or gas contained by the formation. It is important to note that this system involves the possibility of much human error, and is extremely limited in its real-time accuracy, and is not an independent method of determination of the composition of the formation, generally;
4. The closest prior art, in terms of similarity to the present invention, is the electro-mechanical or computer-driven devices of the prior art, which basically comprise an enclosure, suitably mounted to the floor of the oil rig, which contains a rotating drum therewithin, wherein the rotating drum is operatively connected to a rotating reel which carries wire which is fed over a pulley wheel disposed above the kelly and over this pulley down to the top of the swivel. In operation, as the wire is unreeled from said reel, it actuates a suitable marking device, for example, a pen for every foot of penetration or downward movement of the kelly, and therefore the drill string and drill bit attached thereto, wherein the marking pen plots a graph on a sheet of graph paper mounted on the rotating drum. The resultant graph depicts the rate of penetration of the drill bit at various depths of the formation, and this data can be interpreted to form the basis for making a determination of the composition or type and quality of the formation being drilled. Generally, the denser the formation, the slower the rate of the penetration of the drill bit therethrough. However, many deficiencies in this system have made it largely inaccurate and difficult to interpret, inter alia, as will be hereinafter thoroughly discussed.
The system of the present invention features many improvements and advantages over all of these above-delineated systems of the prior art. The system of the present invention comprises a top-surface (i.e. mounted to the rig floor) measuring wheel which transmits an electical signal for each pre-determined penetration of the kelly, and therefore, the drill pipe and drill bit attached to the bottom thereto for drilling the well bore, and this electrical signal is shaped/filtered by an electronic circuit which is interfaced with a small computer, thereby transmitting the signal to the computer which is programmed to process this analog like signal into digital form and plot the resultant data on a chart which depicts the rate of drilling penetration in graphical form. The computer comprises a printer which will produce hard copies on, any desired scale, of the resultant graphical data. A video display is also functionally connected to the computer in order to provide real-time visual display to the user of the system, thereby facilitating an accurate appraisal of the type and quality of the formation being drilled through while the drilling process is transpiring. The advantanges of the present invention are basically as follows:
1. The programmed computer of the present system records the depth for every foot, or any other preselected interval, which the wellbore has been drilled on the graphical output, thereby making said data much easier to interpret than is possible with the systems of the prior art, as these systems generally provide a single, handwritten number at the top of the chart as the only indication of the depth which corresponds to the graphical data being charted;
2. The present system does not record anything when drilling is not occurring, whereas most of the systems of the prior art continuously operate whether drilling is occuring or not, thereby distorting the graphical data which is recorded with improperly correlated data, thereby rendering the data very difficult to properly interpret;
3. The present system provides an electronic circuit which filters and shapes the electronic pulse so as to eliminate any and all irrelevant electrical signals;
4. The present invention has a built-in capability of recording, on several scales, the rate of penetration of the drill pipe on a real-time basis;
5. The accuracy of the graphical output exceeds that presently known in the relevant art;
6. The system provides an accurate continuous log whereas prior systems provided a 24 hour chart that was very difficult to correlate.
7. The present invention is compact, easy to install and use, and much more cost-effective than the relevant prior art;
8. The present invention features an interface modem which can be plugged into the computer to functionally connect the system to a telecommunications system in order to telecommunicate the hard-copied graphical output to any desired location, where the data can be utilized by investors, bankers, engineers, technicians, supervisory personnel, geologists, and any other person who may benefit from knowing the rate of penetration of the drill bit through the formation, in order to properly appraise the quality of the formation and its probability of containing oil and/or gas;
9. This system has proved to be a functional unmanned instrument, capable of producing inexpensive, highly accurate, correlatable logs in six different formats and two different colors;
10. Installation and program initiation can be performed by non-computer personnel.
11. Actual service and diagnosis can be performed quickly by means of a telephone call and corresponding use of the drilling data computer's built in two-button self-test feature.
12. Control functions can also be an output of this system, to control valves lights, alarms, additional recorders, and controls for shutting down systems.
13. The present invention provides a real-time readout of the well log which can be utilized while drilling to correct errors or to properly diagnose the type and the quality of the formation being drilled. It provides a real-time basis for making real-time alterations to the composition of the drilling fluids being circulated through the well bore. By knowing the penetration rate on a real-time basis, supervisory personnel and operational technicians, other personnel can make real-time adjustments to the type of drilling bit being utilized to drill through the formation. Real-time adjustments can be made to the direction of drilling by making a real time determination of the proper point at which to begin the drilling off of the longitudinal axis, i.e., choosing the right sediment/strata to make the first adjustment off of the vertical axis of drilling.
The devices of the prior art are plagued with the problem of generating output which is unreadable by ordinary technicians and workers in the field who cannot accurately interpret the data plotted by the device, as these devices do not provide an output which is calibrated according to the depths at which the measurements correspond to the prior art devices also produce an output regardless of whether the drilling process is interrupted or not. This makes the resultant graphical output generated by the devices very diffcult to interpret by anyone, even skilled personnel. The present invention also has the built-in capability of recording on various scales, by means of the operator of the device merely pressing buttons on the computer terminal, which is conveniently accessible, and the computer automatically makes the adjustment by means of said computer program to produce an output on the selected scale, thereby making the data much easier to interpret on a real-time basis. The devices of the prior art would require one machine for each scale desired, and not only is this expensive, it is very diffult to manage. The device of the present system is much less expensive, easier to install, easier to maintain, and easier to operate, even by an ordinary workman in the field, whereby the real-time graphical output generated by the device of the present invention facilitates optimal drilling of the well bore. The computer program ensures that the graphical output provides a constant time frame reference with respect to the measurement of drilling rate of penetration being continuously recorded on a real-time basis, and further, provides a readout of the depth at every 100 ft. interval or any other interval desired, thereby facilitating accurate and easy interpretation of the graphical data.
The present invention reduces the incidence of downhole wireline operations, which are expensive, require removal of the drill string, which results in rig downtime, eliminates the necessity of contracting with an outside wireline company, and eliminates the necessity of dependence on the accuracy of the equipment and data generated by the equipment utilized in downhole wireline recording operations, such as gamma ray recorders and beta ray recorders. In the context of wireline operations, it is necessary to have a human being, a log analyst, accurately interpret the information being recorded by the gamma ray or whatever type of detector is being utilized. The present invention eliminates this log analyst from the chain of the information gathering process. The present invention could possibly eliminate the necessity of a mud logger continuously working on the rig during the drilling procedure, on a 24-hour basis, which thereby eliminates the substantial cost thereby incurred and human error inherent thereto.
Therefore, in summary, the present invention provides a system for continuously and accurately recording on a real-time basis, the rate of drilling penetration, and which ultimately provides graphical data which can be easily interpreted and utilized for monitoring the drilling process on a real-time basis, thereby facilitating the modification of the drilling process commensurate with the type of formation being drilled. The invention eliminates much of the costs and human error presently attendant to oil rig operations, with the devices of the prior art. Also, it is important to note that the system of the present invention is unaffected by rig power, which has resulted in the failure of many of the devices of the prior art in crucial situations. The programmed computer of the present invention is designed to continuously monitor the shape of, duration of, and any other critical data relevant to, the AC pulse generated by the electrical apparatus situated on the oil rig for powering the oil rig, for any deviations or interruptions thereof. The machines of the prior art, which do not continuously monitor this phenomenon can inaccurately record the data, whereby the computer program of the present invention, upon sensing this phenomenon, makes the necessary adjustments for ensuring an accurate graphical output. Also, the present invention provides a magnetic tape storage system for collecting all of the generated data for future use. Further, the present invention provides a video display screen for displaying the graphical output generated on a real-time basis, to facilitate easier real-time utilization of the data for montioring the drilling as above described.